Military helicopter was shot down, says Afghan president

At least nine people were killed when a military helicopter was shot down in central Afghanistan, President Ashraf Ghani said Thursday.

The ministry of defence said earlier the aircraft had crashed in a volatile district of Wardak province, where Afghan forces and local militias have fought bitterly in recent years.

"Our helicopter was shot down... and our brave pilots were martyred," Ghani said at a ceremony at the presidential palace.

He did not say who was responsible, but warned "the perpetrators of the incident will be seriously punished".

The defence ministry said four crew and five security force members were killed.

Helicopter crashes are common in Afghanistan either due to technical problems or militant attacks.

In October last year, nine members of the Afghan military were killed when two army helicopters collided while transporting wounded soldiers in southern Helmand province. 

The Afghan government has been battling a surge in violence across the country blamed on the Taliban, despite peace talks launched between the two sides last year.

In the Afghan capital, four people were killed and nine others were wounded in a blast targeting a bus in east Kabul on Thursday, police said.